Bellflower is up there, but if I had to use one word, it would be...

SOAPWORT.

Arnica. Got seeds from some wildflower company. Terribly invasive, forms a web of roots everywhere, took forever to get rid of it.

These plants I brought into my garden willingly and I wished I hadn't:
goutweed, lily of the valley, clustered bellflower, orange ditchlily, Centaura montana (perennial bachelor's button), anemone sylvestris, and one hawthorne tree that suckers like crazy and is a bug/disease magnet.

I have some plants that blew in from the wind or from a bird's butt: creeping bellflower, oxalis stricta, and cypress spurge.

Also have a few that are considered garden-worthy plants but can be weedy: zebrina hollyhock, borage, maltese cross, peach-leaved bellflower, rudbeckia...and my ever-lasting struggle with lawn grass and quackgrass growing in my flowerbeds.

My advice to a new gardener: be selective when people want to share pieces of their plants with you, quite often they are invasives that will cause you more trouble in the long run.

Chinese lantern plant inherited from the previous home owner. Spreads like crazy.

I'm up there with the centaurea and another bell flower. The moral of that story is listen to the garden centre guy when he tells you it can be bad. That being said, he could have been more assertive in telling me! LOL Filipendula is also giving me fits, as is polemonium album (white Jacob's ladder). Another one is verbascum. That one has been on my get-rid-of list for many years and there are still plants that come up throughout the flower beds.

Oxalis - yes. No idea where it came from but it has been TERRIBLE!!

Gil, which soapwort are you talking about? Oxcymoides? If so, then me too. When winter sowing, a person needs to beware of seeds that germinate way too easily!

I wish the garden centres actually had people that knew enough to warn you. I had arctic polemonium (blue) that I just got rid of because of mildew. Plus it really was being aggressive.

I started this thread then went to town, of course stopping at the garden center. I was scared to buy anything LOL....i did get a couple more hosta's and a delphinium as well as a chocolate coloured joe pye weed. Petunias were on sale for $8 for 6 - 6 packs so who could resist a little color.

Great list thanks all.

SCG

Not all garden center people know what they are talking about! When we first moved to Florida I asked lots of questions. I guess the girl's brain was out to lunch. Everything I bought grew the way I didn't want it to grow. I grew night blooming Jasmine close to the house because she said it wouldn't get that tall. Well, it was under the eves and it took off like a rocket. The other plant grew like a weed, too. Definitely both were planted in the wrong place.

I would add Shasta Daisies, they were here when I purchased the place. A plant that is very, very bad is Leafy Spurge, it invades grass lands and road side ditches. It is in the process of invading the country side around here and I don't think that it is possible to stop it.

SCG, thanks for starting this great thread! Very good information indeed.

The thing that I regretted bringing in was that darn Arnold Red Honeysuckle. The flowers were not all that impressive, the aphids loved it (despite the Arnold Red variety being supposedly aphid resistant) and the new leaves have a very unattractive form when they emerge. Also, it did not leaf out at all in the old wood this year. That's why it got shovel-pruned...

Now, I am wondering why Centaura Montana is bad? I have planted these centauras which have gold leaves (the Gold Bullion one) and they have not done well yet. The buds somehow died before they bloomed, and the leaves now already look terrible. Is Centaura just generally not a desirable plant?!

Marcia, why is filipendula bad please? It looks so pretty in the photos!!!

Uh oh! I have that anemone sylvestris - what is wrong with it please? Does it spread too much please?

BTW, SCG, when I was in zone 5, I got a Chocolate JPW too - it's PRETTY!!!!!!!!!!! You will enjoy it.

Ostrich, the filipendula is lovely, but spreads by runners and will go all over the place. I should be containing it somehow but haven't done anything besides rip out the ones i don't want.

I forgot about daisies too. I had some that didn't spread but can't remember what kind they were. And also a ranunculus that someone gave me. She said it didn't spread in her garden, but it sure took off here! I've started working at it this summer - almost no use spraying any weed-killer on it because it's been raining all the time.

I am a wannabe zone 5....I am concerned it won't last, then again with my planting style who cares! LOL

frick it is 40.5C outside and everything is wilting like crazy...........

SCG

Cheer up, SCG. It could be 13ð like here! My husband was piling wood and he said he didn't even break a sweat in July. And we have a fire going to take the chill off. Sheesh.

I have the shasta daisy and filipendula as well and although it does tend to wander around, it doesn't seem as bad as some of the others I mentioned in my earlier post.

ostrich,

The anemone sylvestris might be alright if deadheaded but it can spread quite a distance and I don't really like it all that much.

I don't like perennial bachelor's button because there is too much coarse foliage to flower ratio - they get lost in all the leaves....it doesn't help that the plant is so tenacious; I have been trying to get rid if it for years and it keeps sprouting up!

Shasta daises went crazy here also and finally got smart and deadheaded them last summer and only a scant few seedlings are be found now. For the most part, I stopped growing amaranthus, as it seeds out in thick carpets and keeps germinating all summer. The annual silene became a nasty weed in no time flat and now I eradicate every single one that pops up. Rudbeckias have also been heavy seeders, though are easy to keep up on and remain in much favor..

Centaurea montana was too seedy in my garden but it was easy to eradicate once I decided to get rid of it. Same with lamb's ears.

Scabiosa is *almost* too seedy for me but it's also easy to remove. Marcia, yes it was Saponaria ocymiodes. Absolutely the seediest and tough to pull.

I also sorely regret sea holly which is sad because I liked it. It germinates many years later and is horrible to pull out.

Verbascum is absolutely awful unless you deadhead it immediately. Luckily it doesn't spread by roots.

Yes, sea holly can be a bad one, the very dwarf growing 'Blue Hobbit' had spread itself all over the place and was removed for its bad behavior. I've also gotten rid of all veronica except for 'Sunny Border Blue', as I have yet to find a seedling, maybe it's sterile.

The good thing about gardening in a cold climate is that most invasives are not quite as invasive. However some still can be so I moved my bellflower from a bed with good soil to one with large trees that suck the nutrients and water. The bellflower still grows well but I don't mind it spreading there. Same with lily of the valley - under those large trees it spreads slowly.

My nemesis are the self-seeders such as shastas, malva, lamb's ears, red and pink yarrow that I thought I had controlled but they've turned my garden back into a jungle this year. A lot of weeding coming up before they go to seed this year. Even the Walker's Low have turned into thugs so will be severely pruned before long. Nothing is getting fertilized this year, or even watered much`- I won't encourage rampant growth!

One plant that others find invasive but I don't is Centaurea montana and I don't know why. It's fairly well behaved in my garden. Of course I don't fertilize or even water it much.

^ The Centaurea montana wasn't invasive like bellflower, which pops up everywhere and got into the nooks and crannies of my good plants...the problem I have with it is that I can never completely get rid of it. Digging out all I can see and it still manages to survive somewhere in the garden. I don't like plants that overstay their welcome. ;)

You know, I went to take a look at my Centaurea Gold Bullion again - oh goodness me, the foliage has gone really UGLY! It's losing its gold colour and turning chartreuse. Also, it has brown bits and insects damage. The buds have shriveled up and died. It's just a yellow/chartreuse mess right now.... S.P. time, perhaps!? LOL

My Walker's Low is NOTHING but low! LOL! Yes, it is now a giant. I have no idea why these things like Walker's Low Salvia and Geranium Rozanne would be so big here - much bigger than when I grew them in my zone 5 garden before! Yikes...

Oh my, I would not let achillea into my yard here! I had them in my zone 5 yard and it was a horrendous mess. Terrible foliage with awful mildew and then the flowers were not that good looking. It turned my flower bed like some wild-looking thing that I did not care for LOL

Ostrich, you can cut the centaurea right back when it starts looking ugly. It will grow new tidy foliage.

I obviously have a style of garden you all would hate. I have centaurea, clustered bellflower, sea holly, anenome sylvestris (which I'm trying to confine to a single area), and even goutweed. Also Canada violet which is quite a prolific seeder.

The goutweed is under the deck and can't go anywhere. Nothing much will grow there, so I like it.

The one plant I regret planting is forget me nots. I get tired of weeding that one out. I will have it forever because it has seeded everywhere.

LOL north53, I don't think that these are plants that I hate. I just think that these plants need the perfect spot for them to be under control and to look good!

I actually like goutweed but I don't dare to bring it to my yard. However, in my work place, they have a location where grass probably would be too much maintenance and would not grow well anyway, so they put down goutweed instead and it looks nice. It's a nice contained area surrounded by concrete, so it's goutweed well-used.

I just don't have any experience with Centaurea so I am asking for help! LOL! You know, this is my first season with these things and they are looking ugly already - I probably do not have the right location for it! :-)

As for clustered bell flower, I love it! I like all these purple things.

I even like Forget-Me-Not! In fact, I deliberately brought it into my yard this year and I want it to naturalize, to create a sea of blue..... I just love the delicate flowers and the bright blue colour. OK, perhaps I should talk again after a few years, by then I might be changing my tone! LOL!

HAHA, the reason I started the thread was to learn from others...I am horrible at thinking I can 'control' things.

Ostrich-While I am still a wannabe zone 5 how big did your chocolate JPW get? As normal it was an impulse purchase.

Thanks

SCG

SCG, the Chocolate JPW didn't get that big. It was probably about 2-3 feet tall. Nothing like its cousin Gateway or something like that!!! :-)

See, your P.A.D. is just as bad as mine... LOL!

Tried that 'Chocolate' JPW here too but it didn't survive. The common one is extremely hardy, too much so, but I just yank out what I don't want.